JEE Main 2022 · 24 Jun · Shift 1 · Physics Q60

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PhysicsInteger+4 / -1Question 60 of 90

A metre scale is balanced on a knife edge at its centre. When two coins, each of mass 10 g are put one on the top of the other at the 10.0 cm mark the scale is found to be balanced at 40.0 cm mark. The mass of the metre scale is found to be $x\times10^{-2}$ kg. The value of $x$ is ______.

Your answer

Answer and worked solution

Official answer: 6

Torques about the new pivot (40 cm). The coins (20 g) act at 10 cm, 30 cm from the pivot; the scale's weight acts at its centre, 50 cm, 10 cm from the pivot.

Balance. $20\times30=M\times10$ , so $M=60$ g $=6\times10^{-2}$ kg.

Answer: 6

Topics:Equilibrium of rigid bodies

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JEE Main 2022 · 24 Jun · Shift 1, Physics question 60